print as html

internal/writing/html/writer.go

@@ -0,0 +1,96 @@
+// Package html renders an internal.AggregatorWriter as a complete,
+// standalone HTML document built around the same table fragment produced by
+// pretty.PrettyPrinter.RenderHTML. The document includes the Bootstrap 5.3
+// stylesheet via CDN and embeds the raw table fragment without HTML-escaping
+// it so the result opens directly in a browser.
+package html
+
+import (
+	"fmt"
+	"html/template"
+	"io"
+	"time"
+
+	"github.com/nmoniz/any2anexoj/internal"
+	"github.com/nmoniz/any2anexoj/internal/writing/pretty"
+)
+
+// bootstrapCSSURL is the jsDelivr CDN URL for Bootstrap 5.3.3.
+const bootstrapCSSURL = "https://cdn.jsdelivr.net/npm/[email protected]/dist/css/bootstrap.min.css"
+
+// bootstrapIntegrity is the official SRI hash for Bootstrap 5.3.3 css.
+const bootstrapIntegrity = "sha384-QWTKZyjpPEjISv5WaRU9OFeRpok6YctnYmDr5pNlyT2bRjXh0JMhjY6hW+ALEwIH"
+
+// HTMLWriter writes a complete HTML document for an AggregatorWriter.
+type HTMLWriter struct {
+	output  io.Writer
+	printer *pretty.PrettyPrinter
+	title   string
+	lang    string
+}
+
+// NewHTMLWriter builds an HTMLWriter that writes a complete HTML document to
+// w. The printer is used purely as a source for the raw <table> fragment via
+// RenderHTML; this writer never invokes Render or any method that writes to
+// printer's own io.Writer.
+func NewHTMLWriter(w io.Writer, printer *pretty.PrettyPrinter, title, lang string) *HTMLWriter {
+	return &HTMLWriter{
+		output:  w,
+		printer: printer,
+		title:   title,
+		lang:    lang,
+	}
+}
+
+// documentTemplate renders the full HTML page. The table fragment is typed as
+// template.HTML so the template engine emits it verbatim without escaping
+// the angle brackets in the <table> markup.
+var documentTemplate = template.Must(template.New("html").Parse(`<!DOCTYPE html>
+<html lang="{{.Lang}}">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<title>{{.Title}}</title>
+<link rel="stylesheet" href="{{.CSSURL}}" integrity="{{.Integrity}}" crossorigin="anonymous">
+</head>
+<body>
+<main class="container-fluid py-4">
+<h1>{{.Title}}</h1>
+<div class="table-responsive">
+{{.TableFragment}}
+</div>
+<p class="text-muted small">Generated at {{.GeneratedAt}}</p>
+</main>
+</body>
+</html>
+`))
+
+// Render writes a complete standalone HTML document for aw to the configured
+// output. The same HTMLWriter may be reused; each call rebuilds the table
+// fragment from aw so the rendered <tr> count reflects aw's current items and
+// no rows are duplicated across invocations.
+func (hw *HTMLWriter) Render(aw *internal.AggregatorWriter) error {
+	if hw.printer == nil {
+		return fmt.Errorf("html: nil printer")
+	}
+	fragment := hw.printer.RenderHTML(aw)
+	data := struct {
+		Lang          string
+		Title         string
+		CSSURL        string
+		Integrity     string
+		TableFragment template.HTML
+		GeneratedAt   string
+	}{
+		Lang:          hw.lang,
+		Title:         hw.title,
+		CSSURL:        bootstrapCSSURL,
+		Integrity:     bootstrapIntegrity,
+		TableFragment: template.HTML(fragment),
+		GeneratedAt:   time.Now().UTC().Format(time.RFC3339),
+	}
+	if err := documentTemplate.Execute(hw.output, data); err != nil {
+		return fmt.Errorf("render html document: %w", err)
+	}
+	return nil
+}